Dealing with Jealousy and Insecurity in Friendships

I'm becoming increasingly jealous of couples lately. I get really insecure about being single and it's gotten bad to the point where every time I see my roommate and her boyfriend together I get pissed off internally. I don't try to make it obvious but I have thoughts of anger and malicious intent towards them. It's one thing to see random couples I don't know but seeing people I'm friends with happy together romantically makes me increasingly aggressive. I worry I'll become a toxic person around them. How do I manage jealousy and become less insecure about myself?